wget: implement TLS verification with ENABLE_FEATURE_WGET_OPENSSL

When ENABLE_FEATURE_WGET_OPENSSL is enabled, correctly implement TLS
verification by default. And only ignore verification errors, if
--no-check-certificate was passed.

Also note, that previously OPENSSL implementation did not implement
TLS verification, nor printed any warning messages that verification
was not performed.

Bug-Ubuntu: https://bugs.launchpad.net/bugs/1879533

CVE-2018-1000500

Signed-off-by: Dimitri John Ledkov <xnox@ubuntu.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/networking/wget.c b/networking/wget.c
index f2fc9e215..6a8c08324 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -91,6 +91,9 @@
 //config:       patches, but do want to waste bandwidth expaining how wrong
 //config:       it is, you will be ignored.
 //config:
+//config:       FEATURE_WGET_OPENSSL does implement TLS verification
+//config:       using the certificates available to OpenSSL.
+//config:
 //config:config FEATURE_WGET_OPENSSL
 //config:       bool "Try to connect to HTTPS using openssl"
 //config:       default y
@@ -115,6 +118,9 @@
 //config:       If openssl can't be executed, internal TLS code will be used
 //config:       (if you enabled it); if openssl can be executed but fails later,
 //config:       wget can't detect this, and download will fail.
+//config:
+//config:       By default TLS verification is performed, unless
+//config:       --no-check-certificate option is passed.
 
 //applet:IF_WGET(APPLET(wget, BB_DIR_USR_BIN, BB_SUID_DROP))
 
@@ -124,8 +130,11 @@
 //usage:        IF_FEATURE_WGET_LONG_OPTIONS(
 //usage:       "[-c|--continue] [--spider] [-q|--quiet] [-O|--output-document FILE]\n"
 //usage:       "        [-o|--output-file FILE] [--header 'header: value'] [-Y|--proxy on/off]\n"
+//usage:        IF_FEATURE_WGET_OPENSSL(
+//usage:       "        [--no-check-certificate]\n"
+//usage:        )
 /* Since we ignore these opts, we don't show them in --help */
-/* //usage:    "        [--no-check-certificate] [--no-cache] [--passive-ftp] [-t TRIES]" */
+/* //usage:    "        [--no-cache] [--passive-ftp] [-t TRIES]" */
 /* //usage:    "        [-nv] [-nc] [-nH] [-np]" */
 //usage:       "        [-P DIR] [-S|--server-response] [-U|--user-agent AGENT]" IF_FEATURE_WGET_TIMEOUT(" [-T SEC]") " URL..."
 //usage:        )
@@ -137,7 +146,9 @@
 //usage:       "Retrieve files via HTTP or FTP\n"
 //usage:        IF_FEATURE_WGET_LONG_OPTIONS(
 //usage:     "\n        --spider        Only check URL existence: $? is 0 if exists"
-///////:     "\n        --no-check-certificate  Don't validate the server's certificate"
+//usage:        IF_FEATURE_WGET_OPENSSL(
+//usage:     "\n        --no-check-certificate  Don't validate the server's certificate"
+//usage:        )
 //usage:        )
 //usage:     "\n        -c              Continue retrieval of aborted transfer"
 //usage:     "\n        -q              Quiet"
@@ -662,7 +673,7 @@ static int spawn_https_helper_openssl(const char *host, unsigned port)
         pid = xvfork();
         if (pid == 0) {
                 /* Child */
-                char *argv[8];
+                char *argv[9];
 
                 close(sp[0]);
                 xmove_fd(sp[1], 0);
@@ -689,6 +700,9 @@ static int spawn_https_helper_openssl(const char *host, unsigned port)
                         argv[5] = (char*)"-servername";
                         argv[6] = (char*)servername;
                 }
+                if (!(option_mask32 & WGET_OPT_NO_CHECK_CERT)) {
+                        argv[7] = (char*)"-verify_return_error";
+                }
 
                 BB_EXECVP(argv[0], argv);
                 xmove_fd(3, 2);